With the 3DS eShop's closure, the app bridging nearly two decades of Pokemon history is now inaccessible to new users.
Pokemon Bank is - or rather, was - a 3DS app that allows you to transfer Pokemon from the handheld to the cloud storage of Pokemon Home, and through that into the modern games. Between the 3DS Virtual Console versions of Gen 1 and 2 and the convoluted chain of transfers available from Gen 3 through Gen 7, Pokemon Bank supported 19 years worth of Pokemon games.
Bank was always a free app, but previously, to upload and transfer your creatures into Home, you needed to pay for a $5 subscription that got you access to the Poke Transporter companion app. The Transporter app was never available for download without that subscription. However, the Pokemon Company previously announced that Bank and Transporter were going to become free following the 3DS eShop shutdown.
Now that the eShop is closed, you can no longer download software - even free software - unless you had acquired it at least once before. That means that even though Transporter is technically now free, unless you previously paid that $5 subscription fee to download it in the past, you cannot download it now. Neither Nintendo nor the Pokemon Company ever fully spelled out that this would be the case, though you could certainly read between the lines to guess it.
I've never paid for the Bank, and I can personally confirm that the Transporter app is now completely inaccessible. When Bank directs you to download Transporter from the eShop, you'll see the message "this software is currently unavailable." My dreams of someday doing a full Pokemon series playthrough to build a living Pokedex are now completely dead. Ah, well.
Earlier it seemed that Transporter was broken even for players who had properly gone through all the steps, but that was just a glitch - old Bank subscribers can still save their old Pokemon. The rest of us will have to prepare to say goodbye to all our old creatures once those cartridges finally go kaput.
Hopefully this will at least ease the price gouging around retro Pokemon games a bit.